[NARCCAP-discuss] Consistency between tas, tasmax and tasmin.

[Obeysekera, Jayantha]

For this reason, I have stated using values in Table 2 to compute tmax and tmin (although they are based on 3-hourly) values  and stopped using Table 1 values. This was necessary to ensure consistency since I was using other variables in Table 2 for my work.
Obey

Jayantha Obeysekera
Hydrologic & Environmental Systems Modeling
South Florida Water Management District
(561) 682 6503 (Office)
(561) 722 9994 (cell)


-----Original Message-----
From: narccap-discuss-bounces at mailman.ucar.edu [mailto:narccap-discuss-bounces at mailman.ucar.edu] On Behalf Of Seth McGinnis
Sent: Tuesday, February 07, 2012 4:49 PM
To: Discussion of NARCCAP data - uses and questions
Subject: Re: [NARCCAP-discuss] Consistency between tas, tasmax and tasmin.

Hi Blaise,

Thanks for bringing these problems to our attention!  We'll definitely look
further into them.

Cheers,

--Seth


On Tue, 7 Feb 2012 14:59:08 -0500
 "Gauvin St-Denis, Blaise" <GauvinSt-Denis.Blaise at ouranos.ca> wrote:
>Hi,
>
>There seems to be inconsistent behaviour between tas, tasmax and tasmin in
>some narccap simulations.
>
>To frame the problem, we have 3-hourly temperatures (tas) and daily minimum
>and maximum temperatures (tasmin,tasmax). One would expect that:
>tasmin <= tas <= tasmax
>during a given day. Now, some models might have their 'day' start at a
>different hour and compute tasmin/tasmax with respect to the previous 24h, but
>still, this relationship should be valid within at most a 24h offset.
>
>
>Here are the problems I have:
>
>WRFG-CCSM: Offset of multiple days between tas and (tasmin,tasmax). Could this
>be linked to the missing timesteps problems?
>example in attached figure (tasmm_wrfg_ccsm.png): we can see that there is an
>offset of more than 48h.
>
>Note that I did not see this problem in the WRFG-CGCM3 run.
>
>
>
>RCM3: 3-hourly temperatures often overshoot/undershoot the (tasmin,tasmax)
>envelope.
>example in attached figure (tasmm_rcm3_gfdl.png): a few points where the
>3-hourly temperature is well below/over 3 deg. C of tasmin/tasmax
>
>Note that this is present in both RCM3-GFDL and RCM3-CGCM3.
>
>
>
>Any confirmation/comment on those issues would be appreciated,
>
>Thanks,
>
>Blaise Gauvin St-Denis
>Groupe Scénarios Climatiques
>Ouranos
>
>st-denis.blaise at ouranos.ca
>Tel. 514-282-6464 #302

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